[IA64] remove unused function __ia64_get_io_port_base

Not only was this unused, but its somewhat eccentric declaration
of "static inline const unsigned long" gives gcc4 heartburn.
Signed-off-by: Tony Luck <tony.luck@intel.com>

include/asm-ia64/io.h

@@ -120,14 +120,6 @@ static inline void ___ia64_mmiowb(void)
 	ia64_mfa();
 }
 
-static inline const unsigned long
-__ia64_get_io_port_base (void)
-{
-	extern unsigned long ia64_iobase;
-
-	return ia64_iobase;
-}
-
 static inline void*
 __ia64_mk_io_addr (unsigned long port)
 {